Impact printer platen support

Abstract

In a serial impact printer including a platen for supporting an image receptor, the platen having a central shaft and a cylindrical impact absorbing sleeve secured thereto, a platen mounting arrangement is provided which is capable of withstanding rapidly repeating, long duration, high impact loads without generating extraneous noise. The ends of the shaft are captured in seats capable of withstanding, without distortion, a high impact printing force in the impacting direction, and are retained in the seats by spring biased arms which restrain the ends of said shaft from rebound movement in a second direction substantially opposite to the impacting direction.

What is claimed: 
     
       1. A serial impact printer comprising a base over which are disposed a platen for supporting an image receptor, said platen including a central support shaft having ends which are supported, and a cylindrical impact absorbing sleeve secured thereto, a print element having character portions disposed thereon, a print element selector for moving said print element to position a selected character portion at a printing position, a marking ribbon positionable between said print element and said platen, and means for delivering a force to said character portion so as to drive it against said platen, in a first direction with an effective mass of at least 0.5 pounds and an extended contact period of at least 1 millisecond, the improvement comprising, means for capturing said shaft ends as said platen deforms in said first direction and said shaft ends rebound in a second direction, opposite to said first direction, in response to said force being applied to said platen in said first direction, said means for capturing including means for cradling said shaft ends, including a support block extending from said base at each end of said shaft, each of said support blocks having a seat therein opening in said second direction, and resilient means for retaining said shaft ends in contact with said seats with a force directed in said first direction to overcome rebound movement of said shaft ends,   said seats in each block are wedge-shaped, said shaft ends support bearings thereon and are rotatable therein and said bearings are held against said wedge-shaped seats by said resilient means which comprises a roller located at each end of said shaft, and means for biasing each of said rollers against said shaft at a location remote from said bearings, said means for biasing acting directly against said shaft and urging said bearings into said wedge-shaped seats while removing clearance from between the bearing portions of said shaft and said bearings for eliminating vibration therebetween.   
     
     
       2. The serial impact printer as defined in claim 1 characterized in that said resilient means comprises a spring biased roller at each end of said shaft, each of said rollers being movable from a first position for capturing said shaft end to a second position for releasing said shaft end. 
     
     
       3. The serial impact printer as defined in claim 1 characterized in that said resilient means comprises a pivotable arm on which said roller is mounted, a spring connected to said arm for urging said arm toward said shaft, and release means for moving said pivotable arm away from said shaft. 
     
     
       4. The serial impact printer as defined in claim 3 characterized in that a cam follower is located on said pivotable arm, and said release means is pivotable and carries a driving cam thereon interacting with said cam follower to move said pivotable arm away from said shaft. 
     
     
       5. The serial impact printer as defined in claim 1 characterized by further including means for eliminating axial play between said shaft and said bearings and axial platen creep, said means for eliminating including means for continuously biasing said shaft in one axial direction.